JP7164676B2 - Timepiece mechanism with magnetic gears - Google Patents

Description

The present invention relates to the field of magnetic gears formed by a first wheel and a second wheel in magnetic gearing relationship. The first wheel comprises a first magnetic pole arranged in an annulus and forming a first magnetic toothing, and the second wheel comprises teeth or a second magnetic pole made of ferromagnetic material. magnetic poles, and these teeth or second magnetic poles are arranged in a ring to form a second magnetic tooth row.

In particular, the present invention relates to mechanisms for timepieces incorporating magnetic gears.

FIG. 1 shows a magnetic gear 2 comprising a small wheel 4 comprising six radially magnetized bipolar magnets 8 in an alternating configuration and a large wheel 6 . These six magnets are arranged regularly around the central portion of the small wheel 4, thereby forming a magnetic toothing 9 with six magnetic teeth. Said large wheel 6 is arranged in a basic plane in which said small wheel also extends, said large wheel 6 having a ferromagnetic rim with peripheral toothing 7 . The small wheel 4 has a center shaft 32 defining the axis of rotation of the small wheel 4, and the large wheel 6 has a center shaft 34. - 特許庁In the general case where the large wheel 6 also rotates, the central axis 34 of this large wheel 6 defines its axis of rotation. In certain cases, the large wheel is fixed to a support (a plate or bridge of the timepiece movement) and the small wheel rotates around the periphery of the large wheel when the small wheel is driven in rotation by a drive device. It is configured to rotate at

FIG. 2 shows a curve 10 of the magnetic disturbance torque applied to the small wheel 4 as it rotates and “rolls” on a geometric circle about the central axis 34 of the large wheel 6 . showing. The magnetic disturbance torque periodically fluctuates in strength according to the angular position α of the small wheel 4 . This angular position α is measured from a reference semi-axis 30 starting from the axis of rotation 32 of the small wheel 4 and passing through the central/rotational axis of the large wheel 6 . By definition, the reference semi-axis 30 is perpendicular to the axis of rotation of the small wheel 4 . As shown in FIG. 2, the period of the sinusoid 10 corresponds to the central angle between two successive bipolar magnets and thus to the angle through which the pinwheel moves for each step of the magnetic gear 2. handle. That is, the small wheel 4 has one bipolar magnet (which forms a magnetic tooth) aligned with the reference semi-axis 30, or in the space between two magnetic teeth, similar to a traditional mechanical gear. corresponding) to the next bipolar magnet (the one that forms the next magnetic tooth or the next space between two magnetic teeth), and then this next bipolar A magnet is aligned with this reference semi-axis, which simultaneously causes the large wheel 6 to rotate (or the axis of rotation of the small wheel to rotate about the central axis 34 of the large wheel) to the reference semi-axis. From one tooth aligned to the next tooth, this next tooth is then aligned with this reference semi-axis. A corresponding magnetic disturbance torque is also applied to the large wheel. For clarity of illustration, the rotation angles/angular positions indicated by arrows in FIG. ) and thus corresponds to α-180°. Point A in FIG. 2 corresponds to an angle α that is zero or an integer multiple of 360°/N. where N is the number of bipolar magnets 8 and thus the number of magnetic teeth in the magnetic toothing 9 . An angle of 360°/N thus corresponds to the angular period or angular pitch of the magnetic toothing 9 .

The angular positions of the magnetic gear 2 at points A and E of the graph of FIG. corresponds to the position. Points B and D on the graph of FIG. 2 correspond to the two maximum intensities (positive and negative respectively) and thus to the amplitude of the magnetic disturbance torque. It should be noted that the magnetic disturbance torque is generated when no torque is transmitted between the two cars. This magnetic disturbance torque tends to move the bipolar magnet 8 in front of the tooth of the ferromagnetic element of the large wheel 6 , thereby causing the magnetic poles of the small wheel 4 and the large wheel 6 to separate on the reference semi-axis 30 . There is a tendency to align the teeth of the ferromagnetic elements (situations at points A and E of curve 10). The angular position of the two wheels then corresponds to the minimum potential energy of the magnetic gear.

The magnetic disturbance torque can be quite large, in some cases as large as (or even larger) than the magnetic torque that can be transferred between two wheels of a magnetic gear. To overcome this disturbance torque, the drive device driving one of the two cars can provide a torque much greater than the magnetic torque transmitted by the magnetic gear. This prevents it from being blocked. When such blocks occur, the energy consumption is unnecessarily increased. Moreover, since the disturbance torque fluctuates sinusoidally, it causes a relatively large change in the magnetic torque transmitted in the magnetic gear. In fact, when the pinwheel 4 is driven in the positive direction of rotation, the disturbance torque is such that during the first half-angle period of the magnetic toothing 9, each alignment of the bipolar magnet 8 on the reference half-axis 30 From the position, this small wheel 4 is braked and driven during a second half angular period following this first half angular period (see FIG. 2). The same applies to the large wheel 6 over each magnetic period of its magnetic toothing 7, but the mathematical signs are reversed.

The present invention aims to overcome the problem of magnetic disturbance torque in such magnetic gears by eliminating at least a large portion of this disturbance torque.

To this end, the invention relates to a mechanism for a timepiece comprising a magnetic gear formed by a first wheel and a second wheel, said first wheel being annularly arranged and having a first magnetic toothing. and said second wheel has teeth made of ferromagnetic material or a second magnetic pole in an alternating configuration and in an annular configuration , said teeth or said second magnetic poles form a second magnetic toothing magnetically coupled to said first magnetic toothing, whereby said first and second wheels are When one car is driven to rotate, the first car is centered on and linked to the other car of the first and second cars via the magnetic coupling. It rolls on a geometric circle with According to the invention, the timer mechanism is further configured to offset at least a majority of the magnetic disturbance torque imparted to the first wheel due to the magnetic coupling with respect to the first wheel. comprising a ferromagnetic element or set of ferromagnetic elements constituting said magnetic disturbance torque relative to a reference half-axis starting from said central axis of said first wheel and passing through said central axis of said second wheel; The intensity varies periodically depending on the angular position of the first wheel.

It should be noted that the rolling of one of the two cars on a geometric circle centered on and linked to the other car is done without mechanical contact. The radius of the geometric circle depends on the angular pitch of each of the two wheels and the distance between the corresponding central axes of the two wheels. "Magnetic torque" means torque of magnetic force.

In a main embodiment, the ferromagnetic element or set of ferromagnetic elements is adapted to generate a magnetic compensating torque whose intensity varies periodically depending on the angular position of the first wheel relative to the reference semi-axis. and the magnetic compensating torque and the magnetic disturbance torque are phase-shifted substantially by 180°.

In a preferred variant, said ferromagnetic element or said set of ferromagnetic elements is symmetrical with respect to a plane of symmetry comprising said reference semi-axis and said first wheel central axis.

In a preferred variant, said ferromagnetic element or said set of ferromagnetic elements is arranged to generate an overall compensating magnetic attractive force at said first wheel, said overall compensating magnetic attractive force comprising: , aligned with said reference semi-axis and pointing in the opposite direction to the overall magnetic attraction exerted by said second wheel on said first wheel. The present invention will now be described in detail with reference to the accompanying drawings. This is given as an example.

Already described, it shows a magnetic gear according to the prior art. 2 is a graph, already explained, showing the magnetic disturbance torque generated in the magnetic gear of FIG. 1; 1 shows a first embodiment of a mechanism incorporating magnetic gears according to the invention (only the magnetic gears are shown); 4 is a graph showing magnetic compensating torque generated by additional ferromagnetic elements associated with the magnetic gear of FIG. 3; 4 is a graph showing residual magnetic disturbance torque in the magnetic gear of FIG. 3; 1 shows a first variant of a first embodiment according to the invention; Fig. 2 shows a second variant of the first embodiment according to the invention; Figure 2 shows a second embodiment of a mechanism incorporating magnetic gears according to the invention (only the magnetic gears are shown);

A first embodiment of the magnetic gear according to the present invention will be described below with reference to FIGS.

In a first variant, shown in FIGS. 3-5, the magnetic gear 3 is formed by the first wheel 4 and the second wheel 6 described above with reference to FIG. Generally, the first wheel has N first alternating magnetic poles arranged in an annulus, which form a first magnetic toothing. In the variant of interest, the first wheel 4 comprises six bipolar magnets whose magnetization direction is radial, the six outer poles forming the first magnetic teeth 9 . The number of these poles is even because the poles are arranged in a ring so that the poles are in an alternating configuration. Typically, the second wheel comprises a second alternating configuration of magnetic poles with teeth made of ferromagnetic material or in an annular configuration. These teeth or the second magnetic pole form a second magnetic toothing that magnetically couples with the first magnetic toothing, thereby causing one of the first and second wheels to rotate. When driven, one car rolls on a geometric circle centered on and linked to the other car via magnetic coupling. In a variant of interest, the second wheel 6 has a rim made of ferromagnetic material, which forms at its periphery teeth forming a second magnetic toothing 7. . These two wheels 4, 6 extend in the same basic plane so that their magnetic teeth do not touch each other. The magnetic disturbance torque generated between the two wheels 4 and 6 has been described above with reference to FIG.

In order to offset said magnetic disturbance torque, the magnetic gear 3 further comprises a ferromagnetic element 12, which is the first torque due to the magnetic coupling between the two wheels 4 and 6. is arranged with respect to the first car 4 so as to offset and therefore cancel at least a majority of the magnetic disturbance torque (curve 10 in FIG. 2) applied to the first car 4 .

The ferromagnetic elements 12 are preferably arranged in the two wheel base planes of the magnetic gear 3 . This ferromagnetic element 12 has two end portions 13 , 14 extending in the direction of the first toothing 9 of the first wheel 4 . The first end portion 14 is positioned at an angular position of 90° and the second end portion 13 is positioned at an angular position of 270°. Typically, each end portion is positioned at an angle with respect to the reference semi-axis 30 of a value that is (M−1/2)×360°/N. where M is an integer greater than 1 and less than N. However, in one of the more complex variants, in addition to the two end portions, other protruding portions, each located at a different one of the angles defined by the value M within the range 1 to N in the above formula can also be set. An intermediate portion 12A connects these two end portions. The intermediate portion 12A has a partially annular shape extending in the basic plane of the first wheel 4 on the opposite side of the second wheel 6. As shown in FIG. It should be noted that this intermediate portion 12A generates a small magnetic torque in the first wheel 4, which is stronger overall than the magnetic disturbance torque generated by the second wheel 6. The magnetic element 12, mainly the two end portions 13 and 14, generate much less magnetic compensating torque. These two end portions 13 and 14 are arranged to rotate inwards towards the toothing 9 of the first wheel 4 with respect to the circle formed by the middle portion and thus radially I'm on my way.

The ferromagnetic element 12 is arranged to generate a magnetic compensating torque 18 represented by the curve of FIG. 4 as a function of the angular position .alpha. This is a periodic variation in intensity with the same period as the periodic variation in the intensity of the magnetic disturbance torque. Preferably, the magnetic compensating torque and the magnetic disturbance torque have a phase shift of substantially 180°. Preferably, the ferromagnetic element 12 is configured such that the maximum magnitude (amplitude) of the magnetic compensating torque is substantially equal to that of the magnetic disturbance torque. FIG. 5 shows the residual magnetic torque that can be applied to the first wheel 4. FIG. The ferromagnetic element 12 , in particular its two end portions, also has a plane of symmetry 36 which includes the reference semi-axis 30 and the central axis 32 (rotational axis) of the first wheel 4 . This feature is advantageous in preventing the ferromagnetic element 12 from generating a magnetic attraction force on the first wheel 4 oriented perpendicular to the reference semi-axis 30 . Such magnetic attraction is perpendicular to the overall radial magnetic attraction that the second wheel 6 exerts on the first wheel 4, whereby such vertical magnetic attraction is This creates a frictional force of the pivot of the first wheel 4 in the associated bearings (not shown) that define the axis of rotation 32 .

In one refinement of the first variant, the ferromagnetic elements are aligned with the reference semi-axis 30 and the direction of the overall radial magnetic attraction exerted by the second wheel 6 on the first wheel 4. It is configured to generate an overall compensating magnetic attraction force at the first wheel 4 that is in the opposite direction. It should be noted that in the first variant the compensating magnetic attractive force due to the part-annular intermediate portion is already reduced, but this intermediate portion is a low reluctance magnetic contact between the two end portions 13,14. Its magnetic attraction on the first wheel is much less than the radial magnetic attraction that the second wheel exerts on this first wheel. This is because these two attractive forces are not of the same order of magnitude. A second and third variant, shown respectively in FIGS. 6 and 7, form the subject of a particular embodiment corresponding to this refinement.

In a second variant of FIG. 6, the magnetic gear 3A comprises a ferromagnetic element 16 which, in addition to the two end portions 13, 14 described above, has a first There is a compensating portion 15 projecting in the direction of the toothing 9 . This compensating portion 15 is located at an angle of 180° to the reference semi-axis 30 and serves to create most of the compensating magnetic attractive force. It should be noted that the compensating portion 15 has the problem that the overall magnetic disturbance torque applied to the first wheel 4 is increased. However, the ferromagnetic element 16 is such that the two end portions 13 and 14 are mostly, or preferably substantially, the two magnetic torques generated at the first wheel 4 by the second wheel 6 and the compensating portion 15 respectively. Virtually all can be configured to offset. In one preferred variant, the free end of the compensating portion has a partially annular contour centered on the first wheel rotation axis 32 at a minimum distance from the first magnetic toothing 9 and substantially this By enlarging the compensating portion such that it extends over the angular period of the first magnetic toothing, the Additional magnetic torque applied can be reduced. Those skilled in the art will know how to optimize such contours and the angular extent of the free ends of the compensating portions in order to minimize the additional magnetic torque.

In a third variant of FIG. 7, the magnetic gear 3B comprises a ferromagnetic element 22, the intermediate portion 22A of which is oriented in the direction of an angular position which is 180° measured from the reference semi-axis 30. , is closer to the first magnetic toothing 9 of the first wheel 4 and is therefore the smallest distance from this first magnetic toothing at this 180° angular position. ing. This third variant includes a relatively large compensating magnetic attractive force, in particular the overall force exerted by the second wheel 6 on the first wheel 4, without generating a large magnetic torque on the first wheel 4. has the advantage of making it possible to obtain a substantially equal radial magnetic attraction force. In fact, as shown in FIG. 6, the magnetic torque generated by intermediate portion 22A is significantly lower than the magnetic torque generated by intermediate portion 16A of the second variant. Those skilled in the art will know how to optimize the shape of the intermediate portion 22A, especially the shape of its central portion, in order to further reduce the additional magnetic torque imparted to the first wheel.

A preferred variant of the second embodiment of the magnetic gear 3C according to the invention is described with reference to FIG. This magnetic gear 3C has a magnetic disturbance torque ( The feature is that there is another set of ferromagnetic element configurations for offsetting at least most of curve 10). The set of ferromagnetic elements has at least two elements 24 and 26 each arranged at a different angle with respect to the reference semi-axis 30, the angle value being (M−1/2)×360°. /N. where M is an integer greater than 1 and less than N.

As in the first embodiment, in a general variant, a set of ferromagnetic elements are arranged to generate a magnetic compensating torque 18 (see FIG. 4), also with respect to the reference half axis 30. The magnetic compensating torque has the same angular period as the magnetic disturbance torque and is substantially 180° out of phase with the magnetic disturbance torque. is shifting.

In a first preferred variant, the set of ferromagnetic elements is located opposite the second wheel 6 with respect to a geometric plane 38 containing the central axis 32 of the first wheel and perpendicular to the reference semi-axis 30. are mostly located in The set of ferromagnetic elements is therefore arranged to generate a global compensating magnetic attractive force at said first wheel 4 , which is aligned with the reference half-axis 30 . , pointing in the opposite direction to the overall radial magnetic attraction exerted by the second wheel on the first wheel. In the preferred variant shown in FIG. 8, the set of ferromagnetic elements formed by the two elements 24 and 26 is wholly on one side of the geometric plane 38 opposite the second wheel 6. are placed in

In a second preferred variant, the set of ferromagnetic elements is symmetrical about a plane of symmetry 36 containing the reference semi-axis 30 and the central axis 32 of the first wheel. The preferred variant shown in FIG. 8 is also included within this second preferred variant. With such a configuration, the effects described above can be obtained.

3 magnetic gear 4 first wheel 6 second wheel 7 second magnetic tooth train 9 first magnetic tooth train 10 magnetic disturbance torque 15 compensation part 12, 16, 22, 24, 26 ferromagnetic element 12A, 16A, 22A intermediate portions 13, 14 end portions 18 magnetic compensating torque 30 reference semi-axes 32, 34 central axis 36 plane of symmetry

Claims (10)

A mechanism for a timepiece comprising a magnetic gear (3) formed by a first wheel (4) and a second wheel (6),
said first wheel having N first alternating magnetic poles arranged in a ring and forming a first magnetic toothing (9);
Said second wheel has teeth made of a ferromagnetic material or second magnetic poles in an alternating configuration and arranged in an annular shape, said teeth or said second magnetic poles being connected to said first magnetic forming a second magnetic toothing (7) magnetically coupled with the target toothing (9) to form a magnetic coupling, thereby forming the magnetic gear (3);
The timepiece mechanism further transmits at least a majority of the magnetic disturbance torque (10) applied to the first wheel (4) due to the magnetic coupling to the first wheel (4) . a ferromagnetic element (12, 12A, 16) or set of ferromagnetic elements (24, 26) configured to be offset;
The magnetic disturbance torque (10) is relative to the reference half axis (30) passing through the central axis (32) of the first wheel (4) and the central axis (34) of the second wheel (6) . A mechanism for a timepiece characterized by a periodic variation in intensity depending on the angular position (α) of the wheel (4) of 1. The ferromagnetic element or set of ferromagnetic elements is adapted to generate a magnetic compensating torque (18) whose intensity varies periodically depending on the angular position of the first wheel relative to the reference semi-axis (30). is composed of
A mechanism for a timepiece according to claim 1, wherein said magnetic compensating torque and said magnetic disturbance torque are phase-shifted by substantially 180°. said ferromagnetic element or said set of ferromagnetic elements being symmetrical about a plane of symmetry (36) containing said reference semi-axis (30) and said first wheel central axis (32); A mechanism for a timepiece according to claim 1 or 2. The ferromagnetic element or set of ferromagnetic elements is configured to generate a global compensating magnetic attractive force at the first wheel, the global compensating magnetic attractive force being equal to the reference half. 4. Aligned with an axis (30) and oriented in a direction opposite to the overall magnetic attraction exerted by said second wheel on said first wheel. A mechanism for a timepiece according to any one of the preceding claims. Said ferromagnetic elements (12, 16, 22) have two end portions (13, 14) extending in the direction of said first magnetic toothing (9) and these two ends There is an intermediate portion (12A, 16A, 22A) connecting the portions,
Said end portions (13, 14) are each situated at an angle to said reference semi-axis (30) which is (M-1/2) x 360°/N, where M is Timepiece movement according to any one of claims 1 to 4, characterized in that it is an integer greater than 1 and less than N. said ferromagnetic element (16) further comprises a compensating portion (15) projecting from said intermediate portion (16A) in the direction of said first magnetic toothing (9);
Cite claim 4, characterized in that said compensating portion is positioned at an angle of 180° to said reference semi-axis (30) and serves to create the majority of said compensating magnetic attractive force. 6. A timer mechanism according to claim 5, when Said intermediate portion (22A) of said ferromagnetic element (22) is arranged such that, in the direction of an angular position which is 180° measured from said reference semi-axis (30), said intermediate portion is aligned with said first magnetic toothing ( 9), thereby minimizing the distance from this first magnetic toothing at said angular position of 180°. A timer mechanism according to claim 5, wherein: said set of ferromagnetic elements includes two elements (24, 26);
Each of the elements (24, 26) is arranged at an angle to said reference semi-axis (30) that is (M-1/2) x 360°/N, where M is less than 1 A mechanism for a timepiece according to any one of claims 1 to 4, characterized in that it is an integer larger than N and smaller than N. Said set of ferromagnetic elements (24, 26) are arranged with respect to a geometric plane (38) containing said first wheel central axis (32) and perpendicular to said reference semi-axis (30), said second 9. Mechanism for a timepiece according to claim 4 or when claim 4 is quoted, characterized in that it is arranged for the most part on the opposite side of the wheel (6). Said set of ferromagnetic elements (24, 26) are arranged with respect to a geometric plane (38) containing said first wheel central axis (32) and perpendicular to said reference semi-axis (30), said second The whole is placed on the opposite side of the car (6) of
9. Mechanism for a timepiece according to claim 4 or when reciting claim 4, characterized in that:

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